There are very few things that you really cannot express in one language. Usually there are work around a using specific phrases or prepositions. Both French and English are more or less complete in that sense.
For example, in French j’irai (I will go) and je serai allé (I will have gone) are two different tenses. Sure, you can express both meanings in English, but French has a specific tense for “things that will have happened at some point in the future” (and many other besides). On the other hand, English has continuous tenses, which cannot be expressed with just a tense in French: /I am going/ (je suis en train de partir) vs /I go/ (je vais).
Both languages can express both concepts, but they have different shortcuts.
Some of them have mostly the same meaning as others but are only used in written form to express that you feel really intellectually superior to your audience. Such levels of snobbery do not translate to english.
